package org.apache.maven.configuration;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Preprocesses a value from a bean configuration before the bean configurator unmarshals it into a
 * bean property. A common use case for such preprocessing is the evaluation of variables within the
 * configuration value.
 * 
 * @author Benjamin Bentmann
 */
public interface BeanConfigurationValuePreprocessor {

  /**
   * Preprocesses the specified bean configuration value. The optional type provided to this method
   * is a hint (not a requirement) for the preprocessor to resolve the value to a compatible value
   * or a (string) value than can be unmarshalled into that type. The preprocessor is not required
   * to perform any type conversion but should rather filter out incompatible values from its
   * result.
   * 
   * @param value The configuration value to preprocess, must not be {@code null}.
   * @param type The target type of the value, may be {@code null}.
   * @return The processed configuration value or {@code null} if none.
   * @throws BeanConfigurationException If an error occurred while preprocessing the value.
   */
  Object preprocessValue(String value, Class<?> type) throws BeanConfigurationException;

}
